supernova
[ soo-per-noh-vuh ]
/ ˌsu pərˈnoʊ və /
noun, plural su·per·no·vas, su·per·no·vae [soo-per-noh-vee] /ˌsu pərˈnoʊ vi/. Astronomy.
the explosion of a star, possibly caused by gravitational collapse, during which the star's luminosity increases by as much as 20 magnitudes and most of the star's mass is blown away at very high velocity, sometimes leaving behind an extremely dense core.
the star undergoing such an explosion.
Words nearby supernova
Example sentences from the Web for supernova
British Dictionary definitions for supernova
supernova
/ (ˌsuːpəˈnəʊvə) /
noun plural -vae (-viː) or -vas
a star that explodes catastrophically owing to either instabilities following the exhaustion of its nuclear fuel or gravitational collapse following the accretion of matter from an orbiting companion star, becoming for a few days up to one hundred million times brighter than the sun. The expanding shell of debris (the supernova remnant) creates a nebula that radiates radio waves, X-rays, and light, for hundreds or thousands of years
Compare nova
Scientific definitions for supernova
supernova
[ sōō′pər-nō′və ]
Plural supernovae (sōō′pər-nō′vē) supernovas
A massive star that undergoes a sudden, extreme increase in brightness across the electromagnetic spectrum, followed by a more gradual decrease lasting from several days to several months. Supernovae occur when a supergiant star collapses suddenly at the end of its life, condensing its core material into an extremely compact mass that then undergoes a slight rebound. The resulting shock wave sends all matter surrounding the core flying into space, leaving a neutron star or black hole at the site of the core's collapse. Supernovae may also occur when a white dwarf accretes material from a companion red giant star, resulting in an increase in mass that eventually triggers carbon fusion in the core of the white dwarf; the sudden increase in available fuel causes energy to be released in a violent explosion. In both cases the shock waves induce further fusion in the matter surrounding the collapsed core; the many elements resulting from this fusion and from the various other stages of nucleosynthesis over the lifetime of the star are scattered into space. These elements serve as the material from which new stellar and planetary systems are formed; in fact, every heavy element found on Earth is thought to have been the product of supernovae explosions. The last supernova to be observed in the Milky Way was seen in 1604 by Johannes Kepler and was used by Galileo, at his trial, as evidence against the presupposition that the universe never changes. Compare nova.
Cultural definitions for supernova
supernova
[ (sooh-puhr-noh-vuh) ]
A large star in its death throes that suddenly explodes, increasing many thousands of times in brightness.
notes for supernova
Most heavy
elements are created by
nuclear reactions in supernovas and then returned to space.
notes for supernova
In 1987, a supernova was sighted near the
Milky Way galaxy. This supernova provided astronomers with a unique opportunity to test the
theories of the structure of stars.